Roller blind with undercut-free guide rail

ABSTRACT

A roller blind for motor vehicles is provided that includes guide rails at the sides of the deployed blind sheet. These guide rails contain guide grooves without undercuts. Strip-like actuators are used to transfer the forces between the pull rod and the driving device. The actuators are prevented from buckling perpendicularly to the plane of the blind sheet by the guide rails. Due to their shape, the actuators are prevented inherently, i.e. without external assistance, from buckling parallel to the plane of the blind sheet.

FIELD OF THE INVENTION

The present invention relates to roller blinds for motor vehicles.

BACKGROUND OF THE INVENTION

Electrically driven rear window roller blinds are known from the priorart. One such prior art roller blind includes a winding shaft pivotablyseated underneath the rear shelf of the vehicle to which the blind sheetis fastened at one edge. The other edge of the blind sheet is connectedto a pull rod that is guided at its ends in guide rails. The guide railsextend alongside the lateral edges of the rear window, starting from therear shelf or below the rear shelf into the proximity of the upper edgeof the window. In order to place the blind under tension, a spring motorwhich biases winding shaft in the direction for rolling up the blindsheet is usually seated in the winding shaft or alongside it.

The blind sheet is unrolled or stretched out with the aid of strip-likeactuators that run in a buckling-resistant manner in the slot chamber ofthe guide rails. A shared gear motor that is situated next to thewinding shaft approximately at the level of its center is provided todrive the actuators. Guide tubes ending at the gear housing of the gearmotor are provided to connect the gear motor to the lower ends of theguide rails. With the aid of these guide tubes, the actuators run in abuckling resistant manner between the drive motor and the guide rails sothat they can perform their pushing function.

Since the motor is seated relatively close alongside the winding shaftin order to save space, the guide tubes run roughly parallel to thewinding shaft in the area of the gear motor and must be deflected at theguide rails in a direction perpendicular to the winding shaft. Again forspace reasons, the radius of curvature of the guide tubes iscomparatively quite narrow where they open into the guide rails. Theseinstallation conditions require an actuator that is equally flexible inall directions. For this purpose, the guide grooves must undercut toensure buckling-resistant guidance.

The undercut guide grooves make the mounting of the pull rod moredifficult. The guidance members of the pull rod can be introduced onlyfrom the ends of the guide rails. Moreover, the production of undercutguide rails is difficult or expensive, particularly, if they are to beintegrally formed with side trim parts or the roof lining of thevehicles such as by injection molding.

The problems with the prior art arrangement have been described inconnection with a rear window blind. As will be appreciated, similardifficulties are encountered with sun roof blinds that are driven in acomparable manner.

OBJECTS AND SUMMARY OF THE INVENTION

In view of the foregoing, a general object of the present invention isto provided a roller blind for motor vehicles that can be installedsimply and easily.

The motor vehicle roller blind of the present invention includes apivotably seated winding shaft having two front ends. The blind sheet isfastened to the winding shaft at one edge. Another edge of the blindsheet, which is remote from the winding shaft, is connected to the pullrod. Two guide rails for guiding the pull rod are provided on eitherside of the stretched blind sheet. Each of the two guide rails containsa guide groove which, in contrast to conventional designs, is free fromundercuts. Strip-like actuators for moving the pull rod or transferringmovement from the pull rod, run in the guide rails. The actuators have arectangular cross section with a thickness that is matched to the widthof the guide groove. On one flat side, the actuators have teeth withwhich they can be positively driven.

Since the actuators have a rectangular cross section, they areinherently sufficiently stiff in the direction parallel to the plane ofthe stretched blind sheet to be able to transfer pushing forces withoutbuckling out laterally from undercut-free guide grooves. The actuatorsare also sufficiently flexible in the direction perpendicular thereto tobe able to easily match the contour of the two drive gearwheels withwhich they are positively coupled for driving or to be able to be housedin places that have profiles other than straight lines. Thus, theactuation members can at least transmit power between the drive wheelsand the pull rod by pushing.

The roller blind can be handled manually, in which case an arrangementof the type described in detail in DE 10 2006 046 065 and DE 10 2006 046064 can be used, the disclosure of which is incorporated herein byreference.

For a solenoid-operated roller blind, an electrical driving device thatcan be connected to the winding shaft can be provided. Alternatively,the driving gearwheels can be coupled to the electrical driving device.Electrical driving devices for such a roller blind are described indetail in DE 10 2006 046 069, the disclosure of which is incorporatedherein by reference.

The arrangement of the present invention can also be used for rollerblinds in which the lateral edges of the blind sheet do not run parallelto each other. In such cases, a variable-length pull rod is necessary.

Advantageous guidance can be achieved if the guide rails begin at oneend in the proximity of the winding shaft. The guide rails can bearranged parallel or converging towards one another, depending on theshape of the window.

The strip-like actuator expediently can have a flat rectangular shapesuch that the dimensions in the thickness directions can be smaller by afactor of 2 or more than in the width directions of the cross-sectionalprofile.

The driving gearwheel can be a straight-toothed gearwheel if the guiderails run at a right angle to the axis of rotation of the drivinggearwheel. If the guide rails are not at a right angle to the axis ofrotation, the driving gearwheel can be provided with helical gearingsuch that the crest line of the teeth lies at a right angle to thelongitudinal axis of the guide rail. The driving gearwheels can bearranged coaxially to the winding shaft, and the driving motor can becoupled to the winding shaft.

Elastic compensation elements can be inserted between the drivinggearwheels and the winding shaft. In the simplest case, the compensationelements are helical or spiral springs. Considerable space can be savedif the spiral spring is seated in a recess of the driving gearwheel.

In order to protect the load-free section of each actuator againstcontamination and damage, a storage tube can be provided for eachactuator. The storage tube can expediently consist of a flexiblematerial. Moreover, the storage tube can be round.

The description of preferred embodiments below is limited to anexplanation of the aspects that are essential to an understanding of theinvention. It is clear that a number of modifications are possible. Aperson of skill in the art can infer minor details from the figuresalong with the accompanying description. As will be appreciated, thedrawings below are not necessarily to scale. Certain parts may bepresented in an exaggerated size to illustrate important details.Moreover, the drawings are simplified and do not contain every detailnecessary in a practical embodiment.

Other objects and advantages of the invention will become apparent uponreading the following detailed description and upon reference to thedrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic partially cut away perspective view of the rearpassenger compartment of an exemplary motor vehicle equipped with a rearwindow roller blind according to the present invention.

FIG. 2 is a schematic front view of the rear window roller blind of FIG.1.

FIG. 3 is a partial cross-sectional perspective view of one of the guiderails as well as a part of one of the guidance members of the rearwindow roller blind of FIG. 2.

FIG. 4 is a schematic exploded perspective view of the connectionbetween one of the driving gearwheels and the winding shaft of the rearwindow roller blind of FIG. 2.

While the invention is susceptible of various modifications andalternative constructions, a certain illustrative embodiment thereof hasbeen shown in the drawings and will be described below in detail. Itshould be understood, however, that there is no intention to limit theinvention to the specific form disclosed, but on the contrary, theintention is to cover all modifications, alternative constructions, andequivalents falling within the spirit and scope of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1 of the drawings, a rear passenger compartment of anillustrative motor-vehicle is shown. The right interior side is shown inFIG. 1, which is a mirror-image of the cut-away left interior side.Unless otherwise indicated, the descriptions for the right body sidealso apply in a general manner to the left body side. FIG. 1 issimplified; thus, for example, interior body such as reinforcements andmounting elements are not shown, since a representation of them is notnecessary for an understanding of the invention.

The body section 1 of the illustrated motor vehicle includes a roof 2,from which a C-column 3 leads laterally downward to a substructure. Acorresponding C-column is also provided on the opposite side of thevehicle. A lining 4 is provided on the inside of the C-column 3. Theroof 2 transitions into a rear window 5 at its rear edge. The rearwindow 5 is limited on the upper side by a window upper edge 6. Asection 7 of the lateral edges that transitions into window upper edge 6at a corner area 8 is shown in FIG. 1. The lateral edges extend inmirror images relative to one another.

The width of rear window 5 is larger at the level of the belt line ofthe body than in the area of upper window edge 6. A B-column 9 lies adistance in front of C-column 3. A rear right side door 11 is hingedonto the B-column 9. The right rear side door 11 has a window cutout 12that is divided by a vertical strut 13 into a substantially squaresection 14 and a triangular section 15. A rear seat 15 having a rearseat surface 16 and a backrest 17 is also arranged in the interior. Therear seat surface 17 rests upon an understructure 18. A rear shelf 19extends between the rear upper edge of the backrest 17 and the rearwindow 5.

The rear window 5 is provided with a rear window roller blind 21. Onlythe blind sheet 22 of the rear window blind 21 is shown in FIG. 1. Inthis case, additional roller blinds are provided on the side window 12,specifically a blind sheet 23 is provided in square window section 14and a blind sheet 24 is provided in triangular section 15.

The drive system for the side window blind sheets 23 and 24 can havesame configuration as the drive system of the rear window roller blind21. Accordingly, only the structure of the drive system for the rearwindow roller blind 21 is described herein. As shown in FIG. 2, the rearwindow roller blind 21 includes two guide rails 25 and 26 that extendalong the sides of rear window. The guide rails 25 and 26 follow thecontour of the rear window 5 and are arranged and configured so as to bemirror-inverted relative to each other. The guide rails 25 and 26 canconverge to a greater or lesser extent in the direction of roof 2 asdesired.

As the two guide rails 25 and 26 are identical, the internal structureof only guide rail 26 will be described herein. Such description alsoapplies to guide rail 25. As shown in FIG. 3, the guide rail 26 includesan undercut-free guide groove 27 with a shallow rectangular profile. Theguide groove 27 is delimited by two mutually parallel side panels 28, 29as well as a groove bottom 30, and opens outward through a slot 31.

The two guide rails 25 and 26 serve to guide a pull rod 32 to which oneedge of the blind sheet 22 is fastened. The pull rod 32 consists of acenter piece, in which two end pieces 33 and 34 run in a telescopingmanner. The center piece lies, for example, in a tubular loop formed onthe blind sheet 22. The two end pieces 33, 34 are elastically tensionedoutward in the direction of the respective guide rail 25, 26 by springs35.

Each of the two end pieces 33, 34 carries a slider 36 at its free end.The end pieces 33, 34 have cross-sectional dimensions that allow them tofit into the guide groove 27 with some play. The cross-sectional shapeof the slider 36 is matched to the cross-sectional shape of the guidegroove 27, which is for example a shallow rectangle.

The end of the blind sheet 22 remote from pull rod 32 is fastened to awinding shaft 37. A driving device 38 serves to move the blind sheet 22between an extended position in which it is spread out in front of rearwindow 5 and a retracted position in which the pull rod 32 either restson the rear shelf 19 or is retracted through the slot present in therear shelf. The driving device 38 includes two identically formedstrip-like flexible actuators 39 and 40. Each of the actuators 39, 40has a shallow rectangular cross section, with two flat sides 41 and 42.The flat side 42 carries teeth 43. This produces a flexible rack withteeth on one side. The thickness of the actuators 39, 40 corresponds tothe clearance of the guide groove 27. As a result, the two actuators are39, 40 are guided in their associated guide rails 25 and 26 in a mannerresistant to buckling in a direction perpendicular to the plane of theirflat sides 41, 42. Since the two actuators 39, 40 have a bettergeometrical moment of inertia in the direction perpendicular thereto,they can transfer actuation forces onto pull rod 32. Due to their shape,the actuators cannot buckle out laterally through the slot 31 even undera compressive load. To improve the guidance, the actuators 39, 40 can beconnected at their ends to the associated slider 36.

The driving device 38 further includes a gear motor 43 having an outputshaft 44 that is rigidly connected to axle journals 45, 46 of thewinding shaft 36. A front gear wheel 47, 48 is seated on each of the twoaxle journals 45 and 46. Each front gear wheel has teeth 49 on its outercircumferential surface that permit a positive engagement with theassociated actuator 39, 40. The two actuators 39, 40 are pressed in theradial direction against the associated driving gearwheel 47, 48 so asto provide a consistent engagement. Relative to the axis of rotation,each of the actuators 39, 40 rests against the corresponding drivinggearwheel 47, 48 on the same side on which the blind sheet 22 also runsoff of winding shaft 37.

The gear wheel 47 is pivotably seated on the axle journal 45. Generally,the same arrangement applies to gear wheel 48 on axle journal 46. Thekinematic connection by which a drive moment is transferred isillustrated in detail in FIG. 3. The illustration provided in FIG. 3applies similarly to the two driving gearwheels 47 and 48. The drivinggearwheel 47 has a disk-like shape with straight front teeth 49 thatcooperate positively with the teeth 43 of the respective actuator 39,40. The gear wheel 47 has a pot-like recess 52 arranged coaxiallyrelative to the teeth 49, which contains a concentric bearing bore 53with which the gear wheel 47 is pivotably seated on the axle journal 45.The recess 52 forms a spring housing for a spiral spring 54 thatproduces an elastic rotary connection between the axle journal 45 andthe gear wheel 47. For this purpose, the axle journal is 45 is furnishedin the appropriate place with a projecting tab 56 that serves as anabutment for an opening 57 provided at the inner end of the spring. Theexternal spring end likewise contains an opening 58 that can bepositively connected to a tab 59 which points radially inward from theouter circumferential surface of the recess 52.

As follows from the description of function below, the spring carriesout a relative rotation with respect to winding shaft 37, given anappropriate dimensioning of the effective diameter of gearwheel 47relative to the roll body formed by rolled-up blind sheet 22 on windingshaft 37. The magnitude of this relative rotation amounts to roughly onerevolution at most. Thus a spiral spring 54 having a relatively shorteffective path length can be used.

The figures showing the illustrated embodiment are not to scale. Rather,the figures are intended to show the essence of the driving principle.The relevant dimensions of the guide rails 25 and 26 as well as theoutside diameter of the two flexible actuators 39, 40 resultingtherefrom will be well-known to one of skill in the art from practice.

An elastically flexible storage tube 61, 62 can be provided on theopposite side of the respective gearwheel 47, 48 as viewed from therespective guide rail 25, 26. The elastically flexible storage tube 61,62 can be positioned relatively freely in the vehicle corresponding tothe spatial conditions. The manner in which the storage tubes 61 and 62are held stationary are not of importance for an understanding of theinvention. Moreover, a housing, for example, can be provided to surroundthe gear wheel 47, 48. The housing can contain an appropriate tangentialbore for the passage of the associated elastically flexible—actuator 39,40.

The following is a description of the operation of the illustratedembodiment. In this description, it is assumed that the blind sheet 22begins completely rolled up onto the winding shaft 37, i.e. as far aspossible. In the rolled-up condition, the spiral springs 54 contained inthe two gear wheels 47, 48 are under a slight bias tension. Due to thebiasing, the actuators 39 and 40 engaged with them, and thus positivelycoupled to them, are elastically tensioned in the direction of and restagainst the two sliders 35 of the pull rod 32. The bias force of thespiral springs 54 keeps the blind sheet 22 taut between the windingshaft 36 and the pull rod 32. The springs 35 press the sliders 36 andthe ends of the strip-like actuators 39, 40 coupled thereto against theslot bottom 30.

If a user, starting from this position, wishes to deploy the rear windowroller blind 21, he starts the gear motor 43 via an electrical switch.The running gear motor 43 turns the winding shaft 37 together with thetwo axle journals 45 and 46 coupled thereto in the direction associatedwith unrolling blind sheet 22 from winding shaft 37. The two drivinggearwheels 47 and 48 move in the same direction of rotation. Since theireffective diameter matches the outside diameter of the roll body on thewinding shaft when the blind sheet 22 is completely rolled up(corresponding to an open roller blind), the two actuators 39 and 40initially move with exactly the same speed as the pull rod 32, i.e., themovable front edge of the blind sheet 22.

With the progressive unrolling of the blind sheet 22, the roll bodypresent on the winding shaft decreases. Therefore, less of the blindsheet is released per revolution of the winding shaft 37 than the twoelastically flexible, but compression-resistant, actuators 39, 40 wouldtravel for the same angle of rotation. Because of their rigid couplingto the blind sheet 22, the actuators are forced to move at the samespeed as the blind sheet 22, which as a result causes the rotatingmotion of the two driving gearwheels 47 and 48 to be retarded inrelation to the rotating motion of the winding shaft 37. Thereby, thespiral spring 54 is wound more tightly, similar to a clock spring.Depending upon the dimensions and length of the extension travel, themagnitude of the relative rotation between the winding shaft 37 and thedriving gearwheels 47, 48 is limited to approximately one revolution. Atthe conclusion of the extension movement, i.e. when the pull rod 21reaches the upper edge of the window, the tension in the fabric of theblind sheet 22 will therefore be somewhat greater than at the beginning.

The blind sheet is retracted in the reverse direction with the twospiral springs 54 relaxing to a corresponding extent. At the conclusionof the retraction movement, the pull rod 31 rests upon a rear shelf 19,with the remaining residual tension in the two spiral springs 54providing the necessary fabric tension in the blind sheet 22. Since thespiral springs 54 are dimensioned exactly the same on both sides, thesame forces act on the pull rod 31 at each end as well in case of arigid coupling.

Since the drive force is introduced directly at the lower end of the twoguide rails 25 and 26, no complex deflections are necessary to connectthe two actuators 39, 40 to a common power source. Each actuator 39, 40has its own power source, which is positioned such that a minimumdeflection of the actuator 39, 40 is necessary because of the completelystretched straight contour. As a result, the friction decreasesenormously compared to prior art designs. The storage tubes 61 and 62also run straight to a large extent and can be placed as desired in thevehicle since they are flexible.

As the illustrated embodiment additionally shows, the two actuators 39and 40 are under a compressive load in the area of their load-bearingsection (i.e. between the pull rod 32 and the respective drivinggearwheels 47, 48. This applies even in a manual enterprise by way ofthe pull rod. Over the full length of the load-bearing section, thiscompressive load could cause the respective actuator 39, 40 to attemptto buckle out of the guide groove 27 perpendicularly to side walls 28,29. However, the respective actuator 39, 40 is prevented from bucklingout by the two rigid side walls 28, 29. The special shape of the flat,strip-like actuators 38, 40 is sufficient however, to prevent a lateralbuckling-out over the entire length of the load-bearing section withoutthe aid of the guide rails 25, 26.

Thus, undercut guide grooves of the type typically found in the priorart can be eliminated. Guide grooves that are free of undercuts have thegreat advantage that such guide grooves can be injection-molded into thetrim parts of the motor vehicle without any special difficulties. Thetrim parts can include sections of the roof liner as well. The ease ofinjection molding results because undercut-free parts can be easilyreleased from the mold even on an otherwise not straight contour.

A further improvement of the buckling resistance in the directionparallel to the plane of the deployed blind sheet 22 can be achieved ifthe respective actuator 39, 40 is constructed in a sandwich-like manner.For example, each actuator 39, 40 can consist, as shown in FIG. 3, of anelastomeric layer bearing teeth 43 and a spring steel strip 64constituting the back side. The spring steel strip can be very thin, sothat it is also possible, for example, to produce a slightly curvedcontour without difficulty. It is flat in the transverse direction, i.e.the generatrix is a straight line.

If the two guide rails 25 and 26 do not extend parallel to one another,as shown in FIG. 2, but at an angle, it is sufficient if the teeth onthe two gear wheels 47, 48 run somewhat slanted in such a manner thatthe axis of the guide rail 25, 26 stands perpendicularly to the crestline of the tooth which is engaged with the respective actuator 39, 40.The ends of the load-bearing section of each actuator 39, 40 remote fromthe gear wheels 47, 48 are forcibly retained in the guide groove 27 bythe spring-tensioned end pieces 33, 34.

While an exemplary embodiment of the invention has been described inconnection with a rear window roller blind, those skilled in the arewill appreciate that the invention is equally applicable to side windowroller blinds and sun roof shades as well, in the form of flat actuatorsin conjunction with undercut-free guide grooves.

A roller blind for motor vehicles is provided that includes guide railsat the sides of the deployed blind sheet. These guide rails containguide grooves without undercuts. Strip-like actuators are used totransfer the forces between the pull rod and the driving device. Theactuators are prevented from buckling perpendicularly to the plane ofthe blind sheet by the guide rails. Due to their shape, the actuatorsare prevented inherently, i.e. without external assistance, frombuckling parallel to the plane of the blind sheet.

1. A roller blind for motor vehicles comprising: a pivotably supportedwinding shaft having two end faces; a blind sheet having a first edgeconnected to the winding shaft; a pull rod connected to a second edge ofthe blind sheet remote from the winding shaft; two guide rails eachextending on a respective side of the blind sheet when the blind sheetis an extended position unrolled from the winding shaft, each guide railincluding guide groove for guiding the pull rod without any undercuts;two strip-like actuators each being associated with a respective one ofthe guide rails, each actuator running through its respective guide railand having a rectangular cross-sectional shape corresponding inthickness to a width of the guide groove, each actuator carrying teethand cooperating with the pull rod; and two driving gearwheels each beingassociated with a respective one of the actuators, each of the drivinggearwheels being arranged at an end face of the winding shaft; whereinthe actuators are operatively arranged between the driving gearwheelsand the pull rod.
 2. The roller blind according to claim 1, furtherincluding a driving device for the winding shaft.
 3. The roller blindaccording to claim 2, wherein the driving device drives the drivinggearwheels.
 4. The roller blind according to claim 1, wherein the pullrod is configured such that its length is selectively adjustable.
 5. Theroller blind according to claim 1, wherein a first end of each of theguide rails is in the proximity of the winding shaft.
 6. The rollerblind according to claim 1, wherein the guide rails extend parallel toone another.
 7. The roller blind according to claim 1, wherein eachactuator moves in its respective guide groove in a manner resistant tobuckling in a direction perpendicular to the blind sheet in the extendedposition.
 8. The roller blind according to claim 1, wherein eachactuator is flat and has a rectangular cross-sectional configurationwith one flat side bearing teeth.
 9. The roller blind according to claim1, wherein each actuator has a sandwich-like structure with a backcomprising a spring steel band.
 10. The roller blind according to claim1, wherein each driving gearwheel is a crown gear.
 11. The roller blindaccording to claim 1, wherein each driving gearwheel has a helicalgearing configured such that a longitudinal direction of a tooth engagedwith the respective actuator runs at a right angle to the longitudinalaxis of the respective guide rail.
 12. The roller blind according toclaim 1, wherein the two driving gearwheels are connected to the windingshaft.
 13. The roller blind according to claim 1, wherein the twodriving gearwheels are arranged coaxially to winding shaft.
 14. Theroller blind according to claim 1, wherein a drive motor is coupled tothe winding shaft.
 15. The roller blind according to claim 1, wherein acompensation element is arranged between each driving gearwheel and thewinding shaft.
 16. The roller blind according to claim 15, wherein eachcompensation element comprises a spiral spring.
 17. The roller blindaccording to claim 16, wherein each spiral spring is seated in a recessof the respective driving gearwheel.
 18. The roller blind according toclaim 1, wherein an engagement element keeps each actuator engaged withits corresponding driving gearwheel.
 19. The roller blind according toclaim 1, wherein a separate transmission case is provided for eachdriving gearwheel.
 20. The roller blind according to claim 1, whereineach actuator has a separate storage tube for accommodating a load-freesection of the respective actuator when the roller blind is in aretracted position.
 21. The roller blind according to claim 20, whereineach storage tube comprises a flexible material.